The Logical Puzzle - 21 Jun 2007

Solution to June's Puzzle: Same Birthday

What's the probability that, in a group of 23 randomly chosen people, at least two of them will have the same birthday? The answer to this puzzle might seem strange. Most people intuitively assume that the probability is very low. However, the probability that two people in a group of 23 have the same birthday happens to be greater than 50 percent (about 50.7 percent). For 60 or more people, it's greater than 99 percent (disregarding variations in the distribution, and assuming that the 365 possible birthdays are equally likely). The tricky part of the puzzle is that you need to determine the probability that any two people share the same birthday—not a specific two. For the exact solution and some interesting information about the birthday paradox, check out the Wikipedia entry at http://en.wikipedia.org/wiki/birthday_paradox

July's Puzzle: Catching a Train

Two trains race toward each other on a railway segment that's 100 miles long. The trains are traveling at 100mph. An insect flying at 200mph flits from one train toward the other, and as soon as it arrives at the other, it flips its direction and flies back toward the first train. The insect continues bouncing back and forth between the trains until the trains crash. What's the total distance that the insect covers until the moment of the crash?

Discuss this Article 4

The trains are moving towards each other with a combined speed of 2*100=200 mph. They will cover the distance of 100 miles and crash in
100 miles/200 mph = 0.5hr.
In this time an insect that keeps flying between the trains without a stop will cover
200mph*0.5 hour = 100 miles
-Vitaly Komarovsky

Assuming that the insect starts when the distance between the trains was 100 miles and no time was lost and constant speed was maintained during the direction flip by the insect:
- As the two trains are travelling at equal speed, they will cover equal distance before they crash. That makes it 50 miles (100mph over 100 miles). So each will take 30 minutes to reach that mark and collide.
- As per above assumption, the insect will fly 100 miles (200mph, 30 minutes)

From the Blogs

Many organizations today cannot use public cloud solutions because of security concerns, administrative challenges and functional limitations. However, they still need a centralized platform where end users can conduct self-service analytics in an IT-enabled environment....More

It is crucial to move away from data and analytics stored on individual desktop computers. Today’s solutions must promote holistic, collective intelligence. The strong, continued alliance between Microsoft and Pyramid Analytics helps make all this possible....More

To become a truly data-driven enterprise, many business leaders recognize that they must extend the capabilities of self-service business intelligence (BI) and analytics to more of their business users. Many BI tools tackle part of this need, but they don’t offer a complete enterprise solution....More